I am trying to upgrade my WSS_Content Database.

This is my upgrade error file:

Timestamp               Process                                  TID    Area                           Category                       EventID Level      Message  Correlation
04/09/2015 16:11:56.53 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession ajxnm INFO SPContentDatabase Name=WSS_Content 2c23fb9c-fa7e-6075-8be3-3d566de977e4
04/09/2015 16:11:56.53 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession ajxnm ERROR Upgrade [SPContentDatabase Name=WSS_Content] failed. 2c23fb9c-fa7e-6075-8be3-3d566de977e4
04/09/2015 16:11:56.63 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession ajxnm INFO SPContentDatabase Name=WSS_Content 2c23fb9c-fa7e-6075-8be3-3d566de977e4
04/09/2015 16:11:56.63 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession ajxnm ERROR Exception: Invalid object name 'WebParts'. 2c23fb9c-fa7e-6075-8be3-3d566de977e4
04/09/2015 16:11:56.66 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession ajxnm INFO SPContentDatabase Name=WSS_Content 2c23fb9c-fa7e-6075-8be3-3d566de977e4
04/09/2015 16:11:56.66 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession ajxnm ERROR    at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)     at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)     at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)     at System.Data.SqlClient.SqlDataReader.TryConsumeMetaData()     at System.Data.SqlClient.SqlDataReader.get_MetaData()     at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)     at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)     at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)     at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)     at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)     at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)     at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command, CommandBehavior behavior, SqlQueryData monitoringData, Boolean retryForDeadLock)     at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command, Boolean retryForDeadLock)     at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command)     at Microsoft.SharePoint.Upgrade.SPContentDatabaseIntegrity.CheckWebParts()     at Microsoft.SharePoint.Upgrade.SPContentDatabaseIntegrity.Check(SPContentDatabaseIntegrityCheckOptions options)     at Microsoft.SharePoint.Upgrade.SPContentDatabaseSequence.ContentDatabaseDataIntegrityCheck()     at Microsoft.SharePoint.Upgrade.SPContentDatabaseSequence.PreUpgrade()     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.Upgrade(Object o, Boolean bRecurse) 2c23fb9c-fa7e-6075-8be3-3d566de977e4
04/09/2015 16:11:57.69 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession aj0ur INFO No context object 2c23fb9c-fa7e-6075-8be3-3d566de977e4
04/09/2015 16:11:57.69 OWSTIMER (0x1CF8) 0x0CBC SharePoint Foundation Upgrade SPUpgradeSession aj0ur ERROR Upgrade Timer job is exiting due to exception: System.Data.SqlClient.SqlException (0x80131904): Invalid object name 'WebParts'.     at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)     at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)     at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)     at System.Data.SqlClient.SqlDataReader.TryConsumeMetaData()     at System.Data.SqlClient.SqlDataReader.get_MetaData()     at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)     at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)     at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)     at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)     at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)     at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)     at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command, CommandBehavior behavior, SqlQueryData monitoringData, Boolean retryForDeadLock)     at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command, Boolean retryForDeadLock)     at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command)     at Microsoft.SharePoint.Upgrade.SPContentDatabaseIntegrity.CheckWebParts()     at Microsoft.SharePoint.Upgrade.SPContentDatabaseIntegrity.Check(SPContentDatabaseIntegrityCheckOptions options)     at Microsoft.SharePoint.Upgrade.SPContentDatabaseSequence.ContentDatabaseDataIntegrityCheck()     at Microsoft.SharePoint.Upgrade.SPContentDatabaseSequence.PreUpgrade()     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.Upgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Administration.SPPersistedUpgradableObject.Upgrade(Boolean recursively)     at Microsoft.SharePoint.Administration.SPDatabase.Upgrade(Boolean recursively)     at Microsoft.SharePoint.Administration.SPContentDatabase.<>c__DisplayClass2.<Upgrade>b__0()     at Microsoft.SharePoint.SPSecurity.RunAsUser(SPUserToken userToken, Boolean bResetContext, WaitCallback code, Object param)     at Microsoft.SharePoint.Administration.SPContentDatabase.Upgrade(Boolean recursively)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.ReflexiveUpgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.Upgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Administration.SPPersistedUpgradableObject.Upgrade(Boolean recursively)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.ReflexiveUpgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.Upgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Administration.SPPersistedUpgradableObject.Upgrade(Boolean recursively)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.ReflexiveUpgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.Upgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Administration.SPPersistedUpgradableObject.Upgrade(Boolean recursively)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.ReflexiveUpgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.Upgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Administration.SPPersistedUpgradableObject.Upgrade(Boolean recursively)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.ReflexiveUpgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Upgrade.SPUpgradeSession.Upgrade(Object o, Boolean bRecurse)     at Microsoft.SharePoint.Administration.SPUpgradeJobDefinition.Execute(Guid targetInstanceId)  ClientConnectionId:890ed0e6-11d6-4ead-9e51-d44197d8a2a5 2c23fb9c-fa7e-6075-8be3-3d566de977e4

SharePoint 2010 and 2013 do not have the schema to support a table named "WebParts". What I would suggest is that you migrate all Site Collections from this content database into a new content database on the original system (e.g. SharePoint 2010). Take that newly created content database with the migrated sites, then upgrade it to 2013.

This SharePoint install has been 2013 from the start. I get errors about the content database and application not being the same version. This is after installing all of the CUs. When I run a test-spcontendatabase or upgrade-spcontentdatabase and get that error. I noticed that there is not a webparts table in the database and there was not one before the CUs were applied when this was working. I tried to migrate the site collection to a new database and I get the error message:

Move-SPSite : Cannot complete the copy or merge operation because the database schema versions are different.

The fix for that is Upgrade-SPContentDatabase....

So you have a content database that was created in SharePoint 2013 that is exhibiting this issue?